In the construction of naturally lit structures, such as greenhouses, pool enclosures, and sunrooms, glass panel roofs have been employed to allow natural light to shine therein. The glass panels themselves can be mounted in frame-like enclosures that are capable of securing the glass panels and providing a watertight seal. These frame-like enclosures provide for a modular glass roofing system that can be assembled together to form the roof.
Glass panel roofing systems generally provide good light transmission and versatility. However, the cost and maintenance of these systems limits their application and is detrimental to their market acceptance. The initial expenses associated with glass panel roofing systems are the cost of the glass panels themselves as well as the cost of the structures that are employed to support the high weight of the glass. After the initial expenses, the poor insulating ability of these systems and their susceptibility to damage result in high operating and maintenance expenses. This is especially the case in the horticultural industry wherein greenhouse profit margins can be substantially decreased due to these expenditures.
As a result, polymeric panels having multiwall designs have been produced that offer improved impact resistance and improved insulation over glass panel systems. These benefits can provide reduced operational and maintenance expenses. However, the light transmission of polymeric multiwall panels is lower than that of glass, which can reduce a greenhouses overall crop yield. For example, although not bound by theory, it has been estimated that about a 1% increase in overall light transmission can result in about a 5% increase in crop yield. Therefore, for commercial greenhouses, improving the light transmission of roofing materials is very desirable.
Therefore, there is a need for polymeric multiwall panels that can offer improved properties over those previously available.